1. Technical Field
The technical field relates to a frequency divider and a frequency division method thereof and electronic devices using the same.
2. Related Art
Along with the development of wireless communication technologies in recent years, the manufacturing technologies of integrated circuits (IC, especially ICs applied to radio frequency (RF) receivers and transmitters) have changed drastically within a short period. Presently, ICs have been broadly applied in the frequency range of giga hertz (GHz) and are being developed towards higher operation frequencies. As a result, the circuit design at the transmitters and receivers becomes very complicated and high power-consuming and, on the other hand, very challenging. Thereby, how to design a high-frequency RF circuit which offers low power consumption and a stable and low-power regulatable reference frequency for a RF system could be one of today's major subjects.
Frequency dividers play a very important role in genera RF circuits and phase-locked loops (PLL) and are the fundamental/critical circuits in wireless communication systems. The maximum operation frequency of a PLL is usually restricted by the operation frequency range of the first-stage frequency divider. Existing frequency dividers can be categorized into current reuse frequency dividers, injection-locked frequency dividers (ILFD), and regenerative frequency dividers.
A current reuse frequency divider usually offers a high sensitivity and a large bandwidth. However, because a current reuse frequency divider in which transistors are driven with gate input signals has to be implemented with a circuit of cascoded transistors, the normal operation bias of the current reuse frequency divider (i.e., the voltage headroom of the current reuse frequency divider) cannot be reduced due to the number of cascoded transistors. Thereby, in general frequency divider circuit design, a current reuse frequency divider should not be implemented by cascoding multiple current reuse structures.